Why do some scopes have a single sided chestpiece, others a two sided, and still others detachable chestpiece fittings?
Generally speaking, to attenuate certain frequencies. The flat side is equipped with a membrane that is generally referred to as the diaphragm side. The conical or bell shaped side is called the bell. Body sounds generally fall within a frequency range of 50 to 2000 Hz. The diaphragm side is designed to attenuate the lower frequence and accentuate higher frequencies within this range – from 500 to 1000 Hz. The bell size is designed for lower frequencies – from 50 to 500 Hz. Most diaphragm only scopes (ADC 660, 662 and 665 series) are designed for general assessment or blood pressure measurement. Combination scopes (those equipped with both a diaphragm and bell) are designed to provide a broader frequency response. In a typical combination scope, only one side of the chestpiece is “active” at a time. Rotating the chestpiece around its valve stem selects one side and “de-activates” the other. It should be noted that on better quality models there is little or no acoustic leakage from the
